| In this study,a total of 332 Thymallus grubii were collected from the Huma River and the Emur River in the upper reaches of Heilongjiang River from September to October 2020,and the individual biology of age,growth,fecundity,and feeding behavior was studied,aiming to understand their living habits,enrich individual biological data,and provide theoretical guidance for artificial breeding and resource protection,the results of the study are as follows:1.The ratio of male to female Thymallus grubii in the Huma River and Emur River in the Heilongjiang River Basin was 1:1.35,the body length range of the group sample was 49～286mm,the average value was 155.22±56.39mm,and the dominant body length range was 50～200m,accounting for 81.02%of the total sample number.The population sample weight range was 1.98～316.24g,the average value was 76.75±60.87g,and the dominant weight range was 0～150g,accounting for 92.47%of the total sample.The age of Thymallus grubii was composed of 0+-4+ years old,of which 1+-3+ age accounted for a relatively high proportion of 73.19%.2.The results of covariance analysis showed that there were significant differences in length-weight relationship between male and female groups(F=7.545,P=0.006<0.05),the length-weight relationship between male and female individuals needs to be fitted separately,and the male-female relationship was as follows:W♀=1×10-5L3.0571(R2=0.978,n=133).W♂=21×10-5L2.9746(R2=0.982,n=180).The results of t-test showed that there were significant differences between B and 3 in male groups(t=2.26,P<0.05),and between B and 3 in female groups(t=4.12,P<0.001),indicating that both male and female groups of Thymallus grubii were allosteoch-growing.The linear regression model had the highest fitting degree of wheel diameter and body length in Thymallus grubii micro-earstone,and the equation was L=27.274RL+24.65(R2=0.8254,n=332),which was selected as the growth retreat equation for Thymallus grubii.The results of covariance analysis showed that there was no significant difference between male and female groups(F=0.072,P=0.788>0.05),so growth backcalculations could be uniformed.3.Three different growth equations were used to fit Thymallus grubii,and the AIC value and BIC value of the three growth equations were calculated,and the AIC value and BIC value of VBGF were the smallest,indicating that VBGF had the best effect on fitting the growth equation of Thymallus grubii.The growth equations of von Bertalanffy for the length and weight of female and male fennel were fitted,and the results of the analysis of the differences in the growth curves and growth parameters of female and male individuals showed no significant difference(F=0.001,P=0.979>0.05),male and female individuals can be fitted using a uniform growth equation,the equations were as follows:Lt=372.50[1-e-0.194(t+0.833)],Wt=889.41[1-e-0.194(t+0.833)]2.9746,Wt=889.41[1-e0.194(t+0.833)]2.9746;growth rate and acceleration equations:dL/dt=72.27e-0.194(t+0.833)、dW/dt=513.25e-0.194(t+0.833)[1-e-0.194(t+0.833)]2.9746 d2L/dt2=-14.02e-0.194(t+0.833)、d2W/dt2=99.57e-0.194(t+0.833)[1-e-0.194(t+0.833)]0.9746[2.9746e-0.194(t+0.833)-1],the parameters b,k,and t0 are substituted into the inflection point equation tIP=lnb/k+t0,and the inflection point age is 3.56 years,and the corresponding body length and weight are 213.64mm and 170.19g.4.The breeding population of Thymallus grubii in the Huma River and Emur River in the Heilongjiang River Basin is composed of individuals of 2+～4+years old,and the absolute fecundity of individuals was 1128～7519.32(2152.63±905.96)grains.The relative fecundity of body length was 7.47～27.85(11.11±3.01)grain·cm-1;The relative fecundity of body mass was 20.46～28.87(22.99±1.62)grains·g-1;From the multivariate regression analysis,it can be concluded that ovary weight is positively correlated with individual absolute fecundity,standard length relative fecundity and body weight relative fecundity,and the partial correlation coefficient between ovary weight and individual absolute fecundity is higher than that between standard length relative fecundity and body weight relative fecundity.From the best-fit equation,it can be seen that the fit between individual absolute fecundity and ovary weight is the highest(R2=0.9843),and the relationship is F=0.0126m02+234.09mo+520.14;therefore,the best-fit equation between ovary weight and individual absolute fecundity can predict the reproductive ability of the natural population of Thymallus grubii,The main breeding groups of Thymallus grubii are 3+and 4+years old,if the resources of this age group are seriously damaged,it will have an incalculable impact on the continuation and replenishment of the entire population,so it is recommended that the starting age should be greater than 5 years.5.In the Thymallus grubii identified for food identification,no food was found in the stomach of 15 tails,the feeding rate was 85%,and the stomach contained as many as 29 species,mainly composed of benthic animals,small fish,plants,etal.Through the analysis of single indicators and comprehensive indicators of food composition,it can be concluded that the three bait organisms of the Perlidae,Ephemera and Nothopsyche are the dominant species of Thymallus grubii food organisms,and are the main feeding food organisms.The results of the Costello graphical method showed that:(1)Thymallus grubii is a wide-ranging fi sh,and foods such as Anabolia and Phoxinus lagowskii are rare bait for Thymallus grubii;(2)The ecological width of Thymallus grubii had high phenotypic components and high food overlap;(3)The frequency of occurrence of three bait organisms,the Perlidae,Ephemera and Nothopsyche,was relatively high,and it was the main feeding food for Thymallus grubii;The feeding intensity of the female group was slightly higher than that of the male group,and the feeding intensity of the elderly group was higher than that of the younger group.Benthic animals occupy an absolute dominant position in feeding on bait,so Thymallus grubiis a carnivorous fish that feeds mainly on benthic animals. |
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